In recent years, from the point of view of copyright protection, device keys have been used on DVD players and DVD recorders and the like, and prevention of secondary distribution by copying has been prevented by encrypting their contents. As such device keys, for example, CPPM (Content Protection for Prerecorded Media), CPRM (Content Protection for Recordable Media), HDCP and the like have been suggested. CPPM and CPRM are systems in which intrinsic identification information—a so called media ID—is generated and encrypted using a device key possessed upon the device side and an MKB (Media Key Block) which is recorded upon the media side. According to such a scheme, a mechanism is provided which makes it impossible to decrypt a disk which has been copied, since its media ID is different. On the other hand, HDCP (High-bandwidth Digital Content Protection system) is a system in which encryption is performed when outputting a digital signal via a digital interface such as DVI or HDMI or the like, and in which it is made impossible to display an image of protected contents if both sides are not compatible with HDCP.
Now, these device keys are purchased by the maker of the device from license supply companies. For each of the device keys it is necessary to install an ID, all of which are different for each device. In the manufacturing process for a DVD player or the like, after having assembled the main circuit board, these device keys are recorded in a flash memory upon this main board, and thereafter a test is performed to ensure that the keys are properly recorded in the flash memory. However, even though this type of test upon the main board is performed, when testing is performed in a final testing process during the stage in which the main board has been installed in is the DVD player itself, sometimes it is found that the device keys have not been installed properly. Thus, in such a final testing process, the replay device is put into a device keys testing mode in which the serial numbers of the device keys are displayed, in order to test whether or not the device keys have been properly recorded.
Furthermore, in the prior art, an optical disk replay device has been described (in Japanese Laid-Open Patent Publication 2005-63505) which is endowed with a function of specifying the device key in question, when some malfunction has occurred in processing for which a device key is required. Moreover a replay device has been disclosed (in Japanese Laid-Open Patent Publication 2003-22609) which detects in a simple and easy manner whether or not the device key information is normal, and which imposes a limitation upon operation if an anomaly has occurred.
However, even if testing is performed as described above, there is still a fear that simply displaying the serial numbers of the device keys may not be sufficient to prevent the operator who is performing the test overlooking a case in which a device key is not recorded. If the optical disk replay device is (undesirably) shipped just as it is with some device key not being properly recorded, then there is a danger that the product may be returned by the user with a justifiable claim that some encrypted disk cannot be replayed.
Accordingly, the present invention attempts to solve these problems with the prior art, and takes as its objective to provide a replay device which is endowed with a function by which it is possible more reliably to test whether or not device keys for copyright protection have been properly recorded in the digital media replay device or recording and replay device during the manufacturing process.